Resin case providing compatibility between air permeability and water proofing property, and mold for producing such case

ABSTRACT

A through hole ( 50 ) with an annular groove ( 52 ) provided about its periphery is formed in a resin case ( 10 ). The through hole ( 10 ) is covered with a water/oil-repellent film ( 40 ) comprising a porous film ( 44 ). The through hole ( 50 ) makes the resin case ( 10 ) gas-permeable, and the water/oil-replacement film ( 40 ) prevents entry of external water and oil, etc.

TECHNICAL FIELD

The present invention relates to a resin case required to begas-permeable and waterproof, such as a connector-integrated case, etc.housing electric and electronic parts inside.

BACKGROUND ART

Circuits including electronic parts such as transistors, etc., andelectric parts such as motors, etc. used for computers and theirperipherals, are designed on substrates. These substrates, etc. arehoused in resin cases (hereafter called “connector-integrated cases”)wherein connectors are integrally formed. Terminals connected to thesubstrates, etc. protrude from the connectors to the outside of theboxes so that the terminals can be attached to other parts through theconnectors.

FIG. 13 is a perspective view of a conventional connector-integratedcase 100.

FIG. 14 is a cross-sectional view of a connector-integrated case 100′having the same construction as the connector-integrated case 100 exceptthat it has a through hole 500 provided in a lid 300, and is equivalentto a cross-sectional view along the line 14—14, in FIG. 13.

The connector-integrated case 100 comprises a box 200 and a lid 300 madeof resin such as plastic, etc. Inside a connector C provided on one sideof the box 200, there is a plurality of terminals T protruding fromwithin to the outside of the box 200 (see FIG. 14).

This terminal T is connected, at one end, to a circuit of a substrate Bsecured in the box 200 and is attachable, at the other end, to anothermember through the connector C.

After securing a substrate B inside the box 200, a seal packing (notshown) is placed between an end face of the box 200 and the lid 300.Then, the box 200 and the lid 300 are secured with screws, etc (notshown).

The connector-integrated case 100 like this has to be completelywatertight so that moisture may not enter inside.

When there is communication between outside air and the inside of theconnector-integrated case 100, conditions of the outside air such asoutside air temperature and humidity, etc. may influence the substrate Binside the connector-integrated case 100.

In particular, when humid outside air is taken into theconnector-integrated case 100, metal parts such as circuits, etc. of thesubstrate B are corroded by moisture contained in the outside air, oftencausing electrical contact failures.

Therefore, the connector-integrated case 100 must be highly airtight.

On the other hand, when electric and electronic parts in use inside theconnector-integrated case 100 generate heat and the temperature insidethe connector-integrated case 100 increases, the inside air may expandto produce high pressure. Further, under certain conditions, theinternal pressure may become lower than atmospheric pressure, that is,it may become subatmospheric.

In order to cope with the thus-produced difference in pressure betweenthe interior and exterior of the connector-integrated case 100, it isnecessary to provide a through hole in the connector-integrated case100. However, provision of such a through hole Inevitably lowers thewaterproof quality and airtightness.

Therefore, in the past, as shown in a cross-sectional view of FIG. 14, athrough hole 500 is formed in an upper surface of the lid 300 or in aside face of the box 200. The through hole 500 was covered with wovenfabric, etc. preventing moisture and oil content from passing through,and allowing only air to pass, to equalize the internal and externalpressures while maintaining a waterproof quality and airtightness.

An example of a woven fabric preventing moisture and oil content frompassing through and allowing only air to pass is a porous film 400 madeof fluorocarbon resin, etc., which is bonded to the box 200 or to thelid 300 by a double-sided tape or by an adhesive.

Since the porous film 400 covering the through hole 500 is made offluorocarbon resin and the like, the double-sided tape and adhesive,etc. cannot achieve sufficient adhesion, and, as a result, the porousfilm 400 sometimes peels in use.

Therefore, in a certain connector-integrated case, the porous film 400is cut into a circular shape and fitted into a metal ring, which iscrimped to hold the porous film 400. Then the porous film 400, fitted inthe metal ring, is secured to the required position on the box 200 orthe lid 300 by insert molding or further crimping.

The porous film 400 is sometimes bonded at the required position on thebox 200 or lid 300 by heat sealing or laser seizing.

However, it requires processing time to crimp a metal ring to theperiphery of the porous film 400. Further, excessively strong crimpinggives rise to the problem of damage to the porous film 400.

Further, bonding the porous film 400 by heat sealing or laser seizing,requires special equipment, resulting in additional cost. Also, duringsuch procedures, it is difficult to locate the porous film 400 at theproper position with respect to the through hole 500. Further, since itis not possible to exert pressure to the porous film 400, sufficientbonding strength cannot be obtained.

In accordance with the invention, a through hole is provided in a sealedresin case, and the through hole is covered with a water/oil-repellentfilm, which is bonded to the resin case when the resin case isinjection-molded. The resin case comprises a box and a lid covering anopening of the box, and the through hole is provided either in the boxor in the lid. The water/oil-repellent film is a porous film and ispreferably bonded to the resin case by causing the molten resin to enterthe pores of the porous film. In a preferred embodiment, thewater/oil-repellent film is made by laminating a backing comprising athermoplastic material and a porous film, and the backing is melted sothat it is bonded to the resin case. The joint of a periphery of thethrough hole and the water/oil-repellent film preferably form a U-shapedcross-section.

In accordance with another aspect of the invention, a die assembly formanufacturing a resin case comprises a first die having an inner surfaceand an annular protrusion on its inner surface, and a second die havinga cylindrical protrusion receivable in the annular protrusion. Awater/oil-repellent film is fitted into a recess surrounded by theannular protrusion of the first die, and when the first and second diesare closed the resin used to form the resin case is injected between thetwo dies. In a preferred embodiment, a pocket is provided either in therecess of the first die or in an end face of the protrusion of saidsecond die, or in both the recess and the end face.

Since the through hole provided in the resin case of the presentinvention is covered with a water/oil-repellent film, communication ofair is provided between the inside and outside of the case but moisture,etc. in the atmosphere do not enter the case. Also, since thewater/oil-repellent film is bonded to the resin case when the resin caseis injection-molded with molten resin, it is not easily peeled. Further,by using a die of the present invention, the water/oil-repellent filmcan be integrally bonded when molding the resin case.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a connector-integrated case of a first embodiment of thepresent invention; FIG. 1(a) is a perspective view; FIG. 1(b) is avertical cross-sectional view along the line b—b in FIG. 1(a); and FIG.1(c) is an enlarged fragmentary view of FIG. 1(b).

FIG. 2 is a vertical cross-sectional view of a connector-integrated caseof a second embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of a connector-integrated caseof a third embodiment of the present invention.

FIG. 4 shows an automobile light case, which is a resin case inaccordance with the present invention; FIG. 4(a) is a perspective view;and FIG. 4(b) is a cross-sectional view along the line b—b in FIG. 4(a).

FIG. 5 shows a motor case, which is a resin case in accordance with thepresent invention; FIG. 5(a) is a perspective view; and FIG. 5(b) is across-sectional view along the line b—b in FIG. 5(a).

FIG. 6 shows a cellular phone case, which is a resin case in accordancewith the present invention; FIG. 6(a) is a perspective view; and FIG.6(b) is a cross-sectional view along the line b—b in FIG. 6(a).

FIG. 7 shows an outdoor lamp case, which is a resin case in accordancewith the present invention; FIG. 7(a) is a perspective view; and FIG.7(b) is a cross-sectional view along the line b—b in FIG. 7(a).

FIG. 8 shows a copier toner case, which is a resin case in accordancewith the present invention; FIG. 8(a) is a perspective view; and FIG.8(b) is a cross-sectional view along the line b—b in FIG. 8(a).

FIG. 9 is an enlarged fragmentary cross-sectional view of a resin caseusing a water/oil repellent film made up of a porous film only.

FIG. 10 shows dies for manufacturing the connector-integrated case ofFIG. 1; FIG. 10(a) is a cross-sectional view showing a condition inwhich the dies are opened; and FIG. 10(b) is a cross-sectional viewshowing a condition in which the dies are closed.

FIG. 11 shows a die designed to relieve pressing force against thewater/oil-repellent film; FIG. 11(a) is an enlarged fragmentarycross-sectional view in which a pocket is provided in a central regionof an end face of the protrusion of the second die; FIG. 11(b) is anenlarged fragmentary cross-sectional view in which a pocket is providedin a central region of a recess of the first die; and FIG. 11(c) is anenlarged fragmentary cross-sectional view in which pockets are providedin the protrusion of the second die and in the recess of the first die.

FIG. 12 is a view illustrating the flow of resin in a cavity; FIG. 12(a)is an enlarged fragmentary cross-sectional view of aconnector-integrated case molded by the first die with an annularprotrusion; and FIG. 12(b) is an enlarged fragmentary cross-sectionalview of a connector-integrated case molded by the first die without anannular protrusion.

FIG. 13 is a perspective view of a conventional connector-integratedcase.

FIG. 14 is a cross-sectional view of another conventionalconnector-integrated case.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows a resin case 10 of the first embodiment of the presentinvention; FIG. 1(a) is a perspective view of a box 20; FIG. 1(b) is across-sectional view along the line b—b in FIG. 1(a), in which thesubstrate B is housed in the box 20 and a lid 30 is attached; and FIG.1(c) is an enlarged fragmentary cross-sectional view of FIG. 1(b).

The resin case 10 is a connector-integrated case comprising theinjection molded plastic box 20 and the lid 30, wherein the connector Cis provided on one side of the box 20. Hereafter, the resin case 10 iscalled a “connector-integrated case”.

In the connector C, there is a plurality of terminals T protrudingoutwardly from the inside of the box 20.

A conventionally known porous film is , a polytetrafluoroethylene(PTFE), which allows gases such as air to pass through but repelsliquids such as water and oil.

An example of such PTFE porous films is one having micropores of about0.1-3 μ, formed at a density of several billion pores/cm². Examples ofspecific products on the market are “Microtek”, etc. films, of NittoDenko Corp.

This PTFE porous film 44 is laminated on a backing 42 comprising apolyethylene terephthalate (PET) non-woven or woven fabric with awater/oil-repelling property imparted to it to form awater/oil-repellent film 40.

A circular through hole 50 is formed in a bottom portion of the box 20and, on an inner surface of the bottom portion, an annular groove 52 isprovided around the through hole 50.

Consequently, as shown in FIG. 1(c), the cross section around thethrough hole 50 becomes substantially L-shaped, and it comprises a tipend (vertical thin wall) 20 a extending in the shape of L, a mid-portion(horizontal thin wall) 20 b below the annular groove 52, and a base endportion (general portion) 20 c.

On the inner surface of the bottom portion, i.e., on the upper end faceof the tip end portion (vertical thin wall) 20 a, the above describedwater/oil-repellent film 40 is fusion-bonded so as to cover the throughhole 50.

Since the through hole 50 for providing communication between interiorof the case and outside air is formed in the connector-integrated case10, there is no difference in pressure between the interior and exteriorof the connector-integrated case 10.

Further, since the through hole 50 is covered with thewater/oil-repellent film 40 which allows air to pass but preventsliquids such as water and oil, etc. from passing through, oil contentand moisture in the atmosphere do not enter the case 10.

FIG. 2 is a cross-sectional view of a resin case 12 of a secondembodiment of the present invention.

The resin case 12, like the one in the first embodiment, is aconnector-integrated case comprising a box 22 and a lid 32, wherein aconnector is provided on one side of the box 22 and, in addition, athrough hole 50 a and an annular groove 52 a are provided in the lid 32.

Also, the through hole 50 a is covered with the same water/oil-repellentfilm 40 as described above.

FIG. 3 is a cross-sectional view of a resin case 14 of the thirdembodiment of the present invention. This resin case 14 also is aconnector-integrated case, like the one described above, comprising abox 24 and a lid 34. However, a through hole 50 b and an annular groove52 b are provided in one side of the box 24 and the through hole 50 b iscovered with the water/oil-repellent film 40.

These connector-integrated cases 12 and 14 also have the through holes50 a, 50 b in the lid 32 or box 24 so that there is no difference inpressure between the interior and exterior of the connector-integratedcases 12 and 14.

Further, since the through holes 50 a, 50 b are covered with thewater/oil-repellent film 40, moisture, etc. in the atmosphere do notenter the connector-integrated cases 12, 14.

As described above, since it is possible to achieve gas-permeability andwaterproof quality compatibly, the resin case of the present inventionis suitable not only for connector-integrated cases but also for otherapplications.

FIGS. 4 through 8 show an automobile light case 100 a, a motor case 100b, a cellular phone case 100 c, an outdoor lamp case 100 d and a copiertoner case 100 e. Further, in FIGS. 4 through 8, (a) is a perspectiveview and (b) is a cross-sectional view along the line b—b in (a).

A light L is housed in the automobile light case 100 a in FIG. 4, and apower cable D protrudes externally of the case. Further, referencecharacters R and A denote a reflector and a lens, respectively.

A motor is housed in the motor case 100 b of FIG. 5, and the power cableD protrudes externally of the case.

An electric/electronic substrate B, etc. are housed in the cellularphone case 100 c shown in FIG. 6.

The outdoor lamp case 100 d of FIG. 7 comprises a main unit 200 d of thecase and a lid 300 d, and the light L is housed inside.

The copier toner case 100 e of FIG. 8 is filled with toner, which isstirred by a rotating screw S.

These cases 100 a, 100 b, 100 c, 100 d and 100 e have, like thepreviously described connector-integrated cases, through holes 500 a,500 b, 500 c, 500 d and 500 e, which are covered with thewater/oil-repellent film 40.

The positions of the through holes differ according to the cases. In thedrawings, the through holes are provided in the side faces of theautomobile light case 100 a and the motor case 100 b. Also, the throughholes are provided in bottom surfaces of the cellular phone case 100 cand the outdoor lamp case 100 d, and in an upper surface of the copiertoner case 100 e, respectively.

Since these resin cases 100 a, 100 b, 100 c, 100 d and 100 e have thethrough holes 500 a, 500 b, 500 c, 500 d and 500 e, electric/electronicparts such as lights and motors, etc. housed inside do not generateheat. Further, even when outdoor temperature changes, there is nodifference in pressure produced between the interior and exterior of thecases.

Further, since the through holes 500 a, 500 b, 500 c, 500 d and 500 eare covered with the water/oil-repellent film 40, moisture in theatmosphere does not enter the case.

Particularly, with regard to the automobile light case 100 a, thecellular phone case 100 c and the outdoor lamp case 100 d, moisture doesnot enter the cases even when such cases are used outdoor and get wet inrainwater, etc.

Also, with regard to the copier toner case 100 e, the toner does notscatter externally of the case even when the screw S provided insiderotates.

Next, the die for manufacturing the resin case of the present inventionwill be described with reference to a die for manufacturing aconnector-integrated case.

Further, the connector-integrated cases 10, 12, 14 of the embodiments 1through 3 are of the same construction except for the positions of thethrough holes 50, 50 a, 50 b as described above, and are manufactured bythe same method.

Therefore, in the following paragraphs, a manufacturing method of theconnector-integrated case 10 of the first embodiment alone will bedescribed.

FIG. 10 is an enlarged cross-sectional view of a die comprising a firstdie 60 and a second die 70; FIG. 10(a) shows a condition in which bothdies 60, 70 are opened; and FIG. 10(b) shows a condition in which bothdies 60, 70 are closed.

A circular recess 64 surrounded by an annular protrusion 62 is providedin the first die 60, and a cylindrical protrusion 72 located at thecentral portion of the recess 64 of the first die 60 is provided on thesecond die 70.

As shown in FIG. 10(b), a cavity 80 is formed between the two closeddies 60, 70.

When the dies 60 and 70 are opened, the water/oil-repellent film 40 isfitted in the recess 64 of the first die 60 (see FIG. 10(a)) so that aninner surface of the recess 64 and a surface of the porous film 44 ofthe water/oil-repellent film 40 come into contact with each other. Thenthe two dies 60, 70 are closed. When molten resin is injected into thecavity 80 formed between the two dies 60, 70, the backing 42 of thewater/oil-repellent film 40 fitted into the recess 64 of the first die60 is melted by the heat of the resin and becomes integral with theresin to be injection-molded (insert molding).

As described above, by using the die for manufacturing theconnector-integrated case of the present invention, thewater/oil-repellent film 40 becomes integral with the box 20 when thebox 20 is injection-molded. Therefore, the process of attaching thewater/oil-repellent film 40 can be omitted.

Further, it is easy to position the water/oil-repellent film 40 withrespect to the through holes 50, 50 a and 50 b.

Further, since the water/oil-repellent film 40 is melted by heat forbonding to the box 20, the bonding strength thereof is sufficient toprevent the film 40 from peeling.

Further, during the injecting-molding, the water/oil-repellent film isevenly pressed by the molten resin under high pressure (300 kgf/cm²ormore), the molded box 20 and the water/oil-repellent film 40 arestrongly bonded.

As a resin for injection molding when manufacturing theconnector-integrated case, it is desirable to use a resin whosetemperature when being molded is higher than the melting point of thebacking 42 making up the water/oil-repellent film

If PET (whose melting point is 264° C.) is used for the backing 42, aresin having a temperature of 264° C. or higher when being molded, suchas (polybutylene terephthalate (PBT), polyphenylene sulfide (PPS). andpolycarbonate (PC), etc. are suitable as resins for injection molding.

The porous film 44 making up the water/oil-repellent film 40 is easilydestroyed when pressed from the outside. Therefore, when the protrusion72 of the second die 70 is pressed against the water/oil-repellent film40 placed inside the recess 64 of the first die 60, the porous structureof the water/oil-repellent film 40 may be crushed and pores thereof maybe closed.

Therefore, it is desirable to provide a pocket in the recess of thefirst die and/or in the protrusion of the second die so as to relievethe pressing force against the water/oil-repellent film.

FIG. 11 is a fragmentary enlarged cross-sectional view of the die havinga structure in which the pressing force against the water/oil-repellentfilm 40 is relieved; FIG. 11(a) shows that a pocket 76 is provided in acentral region of an end face of the protrusion 72′ of the second die70′; FIG. 11(b) shows that a pocket 66 is provided in a central regionof the recess 64′ of the first die 60′; and FIG. 11(c) shows thatpockets 66, 76 are provided in the recess 64′ of the first die 60′ andin the protrusion 72′ of the second die 70′, respectively.

If the pocket 76 is provided in the end face of the protrusion 72′ ofthe second die 70′ as in FIG. 11(a) and the pocket 66 is provided in therecess 64′ of the first die 60′ as in FIG. 11(b), pressing forces at theinner surface of the recess of the first die and the end face of theprotrusion of the second die can be relieved when the first die and thesecond die are closed. Therefore, the porous structure of the centralportion of the water/oil-repellent film 40 is not crushed.

Further, as in FIG. 11(c), when the pockets 66, 76 are provided in boththe recess 64′ of the first die 60′ and the end face of the protrusion72′ of the second die 70′, the pressing force against thewater/oil-repellent film 40 can be more effectively relieved.

The annular protrusion 62 of the first die 60 not only makes it easy toposition the water/oil-repellent film 40 but also causes the pressure ofresin to be exerted perpendicularly against the water/oil-repellent film40 when the resin is injected into the cavity 80, thus making itpossible to fusion-bond the water/oil-repellent film 40 reliably.

FIG. 12(a) is an enlarged cross-sectional view illustrating a flow ofresin in the cavity of the connector-integrated case of the inventionmolded by using the first die 60 with the annular protrusion 62, andFIG. 12(b) is an enlarged cross-sectional view illustrating flow ofresin in the cavity of the connector-integrated case of the inventionmolded by using a first die 600 without an annular protrusion.

If the first die is not provided with the annular protrusion, it isdifficult to position the water/oil-repellent film 40, as shown in FIG.12(b). Besides, since the molten resin flows parallel to thewater/oil-repellent film 40 as shown by the arrow in FIG. 12(b), an endportion of the water/oil-repellent film 40 may be deformed by thepressure of the resin.

On the other hand, as shown in FIG. 12(a), when the annular protrusion62 is provided on the first die 60, the molten resin flows inperpendicularly to the water/oil-repellent film 40, as shown by thearrow in the drawing, so that the water/oil-repellent film 40 and theresin are efficiently fusion-bonded.

When looking at this from the aspect of the shape of theconnector-integrated case to be molded, the periphery of the throughhole and the melted joint of the water/oil-repellent film form aU-shaped cross-section.

As shown in FIGS. 10 and 11, using the die of the present invention, theannular protrusion 62 is provided on the first dies 60, 60′, and thewater/oil-repellent film 40 is fitted and retained in the recesses 64,64′ surrounded by the annular protrusion 62, so that it is easy toposition the water/oil-repellent film 40, and prevent it from slidingwhen the dies 60, 60′, 70, 70′ are closed.

In the above-described resin case, a water/oil-repellent film 40comprising a backing 42 with a porous film 44 laminated thereon is used.However, it is possible to bond the porous film 44 alone without usingthe backing 42. In this case, it is possible to use dies shown in FIGS.10 and 11. Since the porous film 44 is made of PTFE having a meltingpoint of 327° C. or higher, it is not melted by the heat of the moltenresin (whose melting point is 264° C. in the case of PET) injected intothe cavity. The injected molten resin enters pores of the porous film 44to be integral with it and, as a result of this, the porous film 44 isbonded to the resin case. FIG. 9 is an enlarged fragmentarycross-sectional view of the resin case using a water/oil-repellent film40′comprising the porous film 44 alone.

It is needless to say that the die for manufacturing theconnector-integrated case of the present invention described above canbe used when forming the connector-integrated cases 12, 14 of the secondand third embodiments shown in FIG. 2 and 3.

Further, when manufacturing the resin case shown in FIGS. 4 through 8, adie having a shape suitable for the resin case may be used.

INDUSTRIAL APPLICABILITY

As described above, the resin case of the present invention is made soas to be both gas-permeable and waterproof by the through hole and thewater/oil-repellent film covering the through hole. Thus, while there isno difference in pressure between the interior and exterior of the case,moisture from the outside does not enter the case.

By using the die for manufacturing the resin case according to thepresent invention, it is possible to injection-mold the case andintegrally bond the water/oil-repellent film covering the through hole.Therefore, the water/oil-repellent film can be attached withoutadditional equipment and processes.

Since the annular protrusion is provided on the first die, it is easy toposition the water/oil-repellent film. Also, since thewater/oil-repellent film is placed inside the first die before beingpressed by the second die, it will not slide during the injectionmolding.

Further, since the water/oil-repellent film is bonded to a bondingsurface of the case by the perpendicular pressure of the resin, it canbe bonded with high bonding strength.

What is claimed is:
 1. A sealed case for housing equipment, said casecomprising an injection molded resin body having an interior and anexterior, and having a through hole leading from said interior to saidexterior, wherein said through hole has a periphery, wherein the portionof the resin body surrounding said periphery of the through holecomprises a boss surrounded by an annular groove, wherein said boss hasa radial tip surface, wherein said through hole is covered with awater-repellent, porous, film which is permeable to air, but impermeableto liquids, wherein said water-repellent film overlies and is bonded tosaid tip surface by entry of said molten resin into pores of said filmdue to pressure applied to the molten resin when said molten resin isinjection-molded, and wherein only one side of said film is bonded tosaid boss.
 2. A sealed case according to claim 1, wherein said casecomprises a box and a lid covering an opening of said box, and saidthrough hole is provided in said box or said lid.
 3. A sealed caseaccording to claim 1, wherein said film is also oil-repellent.
 4. Asealed case according to claim 2, wherein said film is alsooil-repellent.
 5. A sealed case for housing equipment, said casecomprising an injection molded resin body having an interior and anexterior, and having a through hole leading from said interior to saidexterior, wherein said through hole is covered with a water-repellentfilm which is permeable to air but impermeable to liquids, wherein saidthrough hole has a periphery, and wherein the portion of the resin bodysurrounding said periphery of the through hole comprises a bosssurrounded by an annular groove, and wherein said boss has a radial tipsurface, and said water-repellent film overlies, and is bonded to, saidtip surface by heat and/or pressure applied by the molten resin of whichsaid resin body is formed when said molten resin is injection-molded,and only one side of said film is bonded to said tip surface of saidboss.
 6. A sealed case according to claim 5, wherein said film is alsooil-repellent.
 7. A sealed case according to claim 5, wherein saidwater-repellent film is bonded to said tip surface by entry of saidmolten resin into pores of said film due to pressure applied to themolten resin when said molten resin is injection-molded.
 8. A sealedcase according to claim 7, wherein said film is also oil-repellent.
 9. Asealed case according to claim 5, wherein said water-repellent film is alaminate comprising a thermoplastic backing material and a porous film,and wherein said backing material is bonded to said tip surface bymelting of the backing material by heat applied by said molten resin.10. A sealed case for housing equipment, said case comprising aninjection molded resin body having an interior and an exterior, andhaving a through hole leading from said interior to said exterior,wherein said through hole is surrounded by a radial peripheral surface,wherein said through hole is covered with a water-repellent, porous,film which is permeable to air, but impermeable to liquids, wherein saidwater-repellent film overlies and is bonded to said radial peripheralsurface by entry of molten resin from said resin body into pores of saidfilm as a result of the application of heat and/or pressure to saidresin body, and wherein only one side of said film is bonded to saidresin body.
 11. A sealed case according to claim 10, wherein said filmis also oil-repellent.
 12. A sealed case for housing equipment, saidcase comprising an injection molded resin body having an interior and anexterior, and having a through hole leading from said interior to saidexterior, wherein said through hole is surrounded by a radial peripheralsurface, wherein said through hole is covered with a water-repellent,porous, film which is permeable to air, but impermeable to liquids,wherein said water-repellent film overlies and is bonded to said radialperipheral surface, wherein said water-repellent film is a laminatecomprising a thermoplastic backing material on one side and a porousfilm on the other side, wherein only said one side of said film isdirectly bonded to said resin body, and wherein said backing material isbonded to said resin body by a bond composed of a solidified moltenmaterial, said molten material consisting of molten resin of the resinbody and molten thermoplastic of said backing material integrated witheach other.